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1. Field of the Invention
This invention relates to the field of soil erosion control. More specifically, the invention comprises a new method of manufacturing and packing sections of silt fence.
2. Description of the Related Art
Soil erosion is a constant problem in construction work, where the bare soil must often be left exposed to rain for considerable periods. Traditionally, hay bails were staked to the ground in order to slow water run-off down bare slopes. While effective, this technique was labor intensive and had inherent shipping and storage problemsxe2x80x94owing to the weight of the bales. The more modem approach is to use silt fencing.
A silt fence is a porous barrier fabric which is attached to and stretched between a number of stakes. The stakes are driven into the ground in positions needed to stretch the fabric across the anticipated direction of water flow. The fabric is designed to allow the passage of water, but to encourage the deposition of any sediment being carried in the water. The result is that sediment builds up on the upstream side of the fabric, with the silt fence ultimately tending to bury itself.
Numerous prior art patents pertain to silt fences and methods of producing and installing them. These prior art patent include U.S. Pat. Nos. 6,158,923, 6,053,665, 5,944,114, 5,921,709, 5,915,878, 5,622,448, 5,345,741, and 4,756,511.
FIG. 1 illustrates a typical prior art silt fence. A plurality of evenly spaced stakes 12 are provided. Silt fabric 10 is placed over stakes 12, then affixed to stakes 12 by staples or other fastening means. The user places the fence in position by driving points 16 of stakes 12 into the ground, with the lower portion of silt fabric 10 being buried in a shallow trench.
While FIG. 1 illustrates the components of a silt fence, it does not accurately reflect how such fences are typically manufactured. FIG. 2 shows roll 28, which is formed by a plurality of stakes 12 attached to silt fabric 10. A silt fence is typically made by chucking center stake 36 in a rotating carriage, then attaching the starting end of silt fabric 10 to it. Center stake 36 is then rotated to wind silt fabric 10 around itself. At fixed intervals, another stake 12 is brought in and stapled to silt fabric 10. The winding continues until a complete roll 28 is formed. It is then taped, tied, or banded to lock it in position for transportation and storage.
FIG. 2 illustrates roll 28 having eight stakes 12. Roll 28 can be made larger or smaller. Those skilled in the art will realize that the prior art manufacturing process described is an intermittent one; i.e., once a roll is formed, the process is stopped to remove that roll and start forming a new one. This represents a disadvantage, in that it limits the speed of production. It also causes problems with any printing performed on silt fabric 10. Many purchasers want to have their names and logos printed on the silt fabric itself The best printing methods for this purpose are those using a wet printing plate. The printing dyes employed are dissolved in a liquid carrier, which must be quite volatile (in order for the printing to dry rapidly). Thus, the wet printing process is very sensitive to any pauses in the production. If the feed of silt fabric 10 is halted for significant periods, the dye solutions will dry on the printing plate and the print quality will deteriorate. The prior art intermittent production process therefore compromises printing quality on silt fabric 10.
The roll method has two additional drawbacks. First, rolls 28 do not stack efficiently, since their circular cross section inherently produces wasted space. Second, roll 28 is cumbersome to install. Those skilled in the art will realize that roll 28xe2x80x94as illustrated in FIG. 2xe2x80x94is modestly sized. Often these rolls will be 100 feet long. A typical installation would be in the range of 100 feet to 10,000 feet long. It is very cumbersome to unroll many hundreds of feet of silt fencing packaged in the roll form.
It is also fairly common to need a length which is less than the entire roll. In such a case, the user must lift roll 28 by its ends and unroll the needed amount. The user then cuts the needed amount free from the rest of the roll. As roll 28 can be heavy, this approach often means that two people are needed.
Alternatively, the user can unroll roll 28 by rolling it along the ground until the needed amount is laid flat. The user then removes the needed amount and re-rolls roll 28. This approach requires the user to lift a heavy object (roll 28) off the back of a truck, perform the operation, and then lift it back on to the truck.
Accordingly, the prior art methods of packing silt fencing are limited in that they:
1. Typically require an intermittent manufacturing process, thereby limiting production speed and compromising print quality;
2. Do not lend themselves to efficient packing; and
3. Render the silt fence cumbersome to deploy.
The present invention eliminates the disadvantages inherent in the prior art by placing the silt fence in a flat-pack configuration. With reference to FIG. 4, stakes 12 are evenly spaced and silt fabric 10 is evenly draped over them by any suitable means to form a series of loops 14. Silt fabric 10 is then attached to each stake 12 at the point where it drapes over each stake 12.
Stakes 12 are then moved closer to each other as shown in FIG. 6, with the result that loops 14 grow longer and more narrow. FIG. 7 shows stakes 12 bunched tightly together, with the result that loops 14 are now very long and very narrow. As stakes 12 are held in position, loops 14 are then wrapped around stakes 12 as indicated by the arrow.
FIG. 8 shows stakes 12xe2x80x94still being held in positionxe2x80x94with loops 14 wrapped around them. In FIG. 9, securing straps 24 have been placed around the assembly to create flat pack 26. This entire process can be carried out on a linear assembly line without intermittently stopping the motion.
The objects and advantages of the present invention are:
1. To provide an improved method of packing and storing silt fence which can be carried out on a linear assembly line without intermittently stopping the linear motion;
2. To provide an improved method of packing and storing silt fence which does not waste storage space; and
3. To provide an improved method of packing and storing silt fence which enables the user to easily pull off a short section of silt fence without having to lift the entire pack.